In this Edition
- Autumn residuals essential to get the best from and protect spring herbicides
- Kerb Weather Data Tool
Autumn residuals essential to get the best from and protect spring herbicides
Whether your challenge is ryegrass, brome or poppy, using a residual herbicide in autumn is an essential part of a weed control strategy – to both achieve high levels of control and prevent weed resistance occurring.
Trials work by Corteva Agriscience™, over a number of years, has shown that for control of sterile brome the use of the residual Crystal (Pendimethalin + Flufenacet), applied either pre-emergence or peri-emergence of the winter wheat, followed by Broadway® Star (in autumn or spring) consistently gave outstanding control. Similar results have been obtained for ryegrass control with the use of Prosulfocarb (Defy) as a residual herbicide followed by Broadway Star. Alex Nichols, Cereal Herbicide Product Manager points out “The reason we see better results with Broadway Star applications when used in a programme is principally due to the fact that the residual herbicide either completely takes out or heavily retarding the growth of some of the early emerging grassweeds, this then means that when the contact herbicide Broadway Star is applied (often in the spring) it is dealing with smaller, later emerging weeds. Trying to control a sterile brome plant that germinated with or soon after the crop, would, in the spring, leave a plant that is far too big to be controlled effectively by a selective herbicide. It is also important to note that residual herbicides can also have their performance impaired by poor seed beds and dry conditions”.
The use of a programme is also a key mechanism for reducing the risk of resistance developing. Alex Nichols remarks “Using different modes of action is a well understood tactic for avoiding the development of weed resistance. It stands to reason that by using a programme you put yourself in a position of achieving very high (99%+) levels of control and significantly reducing seed return. Whereas without a programme it is likely that more weeds would survive the application due to being too big for effective control and increasing the number of surviving plants and weed return which will increase the risk of resistance developing.”
It’s not only grassweeds that need consideration, broad-leaved weed control in winter cereals can benefit from a programme with residual herbicides.
“Relying on spring applied contact broad-leaved weed herbicides alone is a recipe for problems – weeds will be either too big for effective control and the probability of resistance developing will be high.”
In situations where ALS resistant poppy is present on the farm, using Stomp Aqua (pendimethalin) in the autumn is a key way of getting control of the large flush of weeds that follows drilling, this can then be followed by application of Zypar™ in the spring, targeting weeds at the 4-6 leaf stage.
Kerb Weather Data Tool
Corteva Agriscience agriculture division of DowDuPont have updated and refreshed the Kerb Weather Data (KWD) tool on our website http://uk.dowagro.com/kerb-weather-data-service/ (available from mid-October).
New for 2018, the refreshed tool not only provides old favourites such as a postcode soil temperatures and moisture, but also rainfall and wind predictions that help growers and advisors plan their spraying workload but a new national soil temperature summary.
If you use ASTROKerb or Kerb Flo 500 when the traffic light is on red, soil temperatures may be too high, propyzamide will breakdown quickly and blackgrass control may be compromised.
In forward crops, large canopies may be closing in rows before the KWD tool indicates green for go. Dow AgroSciences trials over a number of years have shown blackgrass control from propyzamide is not impeded by large crop canopies.
Always adhere to stewardship guidelines especially with respect to water, help ensure we keep essential active ingredients in our armoury to help grow our crops.
If you require any further information please contact our Technical Hotline on 0800 689 8899 or your local Corteva Agriscience representative.
Use plant protection products safely. Always read the label and product information before use.
Pay attention to the Risk Indication and follow the Safety Precautions on the label.
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AstroKerb contains aminopyralid and propyzamide
Broadway Star contains pyroxsulam and florasulam
Kerb Flo 500 contains propyzamide
Zypar contains Arylex and florasulam
Corteva Agriscience, Agriculture Division of DowDuPont, CPC2, Capital Park, Fulbourn, Cambridge, CB21 5XE. Tel: +44 (0) 1462 457272.